Fungus gnats are more prevalent in the winter on house plants. They are attracted to the moist soil and although they cause no damage to healthy plants, they are still a nuisance and can spread to other plants. Fungus gnats are prevalent where plants are too wet; potted in containers that are too big for the plant size; or potted into containers that have no holes for drainage.
Look for small insects on the surface of the soil or flying around. They will be most active when you move or water the plant. The larvae are 1/4” white maggots with black heads under the soil. Fungus gnats feed on dead or decaying plant material so keep plants clean from fallen leaves or debris.
Avoid Fungus Gnats